There are times when the patent system can pass for a useful tool for protecting innovation. And there are times when it resembles a cross between a Whitehall farce and an extortion racket

The latter description seems apt today, with the news that Microsoft has been granted a patent for converting programming objects into XML files and back again. In other words, using XML — the open standard that we all rely on to handle the exchange of data — to do exactly what XML was designed to do. Microsoft has filed some choice nonsense in the past, but it seems that it's getting bolder.

Try visiting the US patent office site where 59 patent applications from Microsoft were published last week alone. Microsoft staff dream up their fair share of bright ideas (even though their bosses are partial to buying up other people's), but calling some of these applications frivolous would imply far too much intellectual rigour.

Take this application for "Efficient string searches using numeric keypad". The details of this work of genius: "Contacts are stored in memory on a mobile device with a limited input device containing input points. Each input point corresponds to a subset of the alphabet. For each contact, a string comprising characters representing the input points that correspond to the letters of the alphabet contained in the name of the contact is generated and saved with the contact in the memory. When a user desires to retrieve a contact, the user presses the input point that corresponds to the subset of the alphabet containing the first letter in the name of that contact. A prefix search for the character representing that input point is performed on the saved generated strings. Any contacts containing a matching string are then presented to the user. "

That's what we, you and a billion others do every day when we look up contacts in our mobile phones — and what Microsoft is claiming to have recently invented. It may be that nobody involved in that patent has ever seen, owned or operated a mobile phone. It may be that Microsoft's patent lawyers are genuinely unaware of the concept of prior art. It may be that Microsoft is gaming the system, taking advantage of patent office docility to create a legal minefield disguised with only the very faintest veneer of innovation. Whichever is the case, the system has failed.

But what could possibly prevent multi-billion dollar companies abusing the patent system? How about the same kind of powers that the sporting world uses to keep competitors within the rules? Today's millionaire footballers are immune to financial penalties — so they get slapped with bans if they step out of line. The world of horseracing is haunted by the fear that races are fixed — so those guilty can be 'warned off', and told never to return to the betting ring.

The only way to make companies respect the patent system is to take the same approach. Those guilty of repeatedly filing frivolous patents don't deserve the protection of the patent system, and should be banned from taking part in it. It's time to red card the worst offenders, before the whole damn system takes an early bath.